• Elastomers and Composites
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• v.48 no.3
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• pp.221-224
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• 2013

In this study, VOC analysis method of vehicle interior materials and parts treated to visible-light responsive photocatalyst was tested by sample bag filled with air instead of nitrogen. As a result, when analyzed VOC of vehicle interior materials and parts, sample bag filled with the nitrogen was not confirmed of effect reducing VOCs and formaldehyde. However, VOCs and formaldehyde of sample bag that was filled with air instead of nitrogen, decreased significantly. Reaction effect for visible light-responsive photocatalyst was confirmed that sample bag of vehicle interior materials and parts should be filled with air instead of nitrogen.

• Elastomers and Composites
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• v.54 no.4
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• pp.279-285
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• 2019

Bio-based polyester polyols were synthesized using esterification with azelaic acid, sebacic acid, and 1,3-propanediol. Polyurethanes were prepared using chain extenders (1,4-Butanediol, 1,3-Propanediol, and isosorbide) and 4,4'-diphenylmethane diisocyanate with a mixing ratio of 1:1:1.1. Subsequently, the properties of the polymers prepared using the different chain extenders were compared. The synthesis of polyurethane was confirmed by FT-IR, TGA, and GPC. The mechanical properties (hardness, ball rebound, and tensile strength) of the materials were analyzed using shore A tester, taber abrasion, and UTM. heat, chemical, and water resistances of the prepared materials were measured by comparing the tensile strengths according to external changes.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.525-528
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• 2002

The speed of sound, transmission coefficient, and attenuation are measured around the center frequency 1 and 2 MHz in solid materials such as bone, sediment, rubber, and Lucite materials. Common and different characteristics of such materials in the sound speed, transmission coefficient, and attenuation are discussed. Ambiguities in estimating such acoustic characteristics we also addressed. Ultrasonic properties of the first and second kind waves are clarified for different materials. Discussions are concentrated on classes of sound speed, broadband ultrasonic attenuation (BUA), and correlations of sound speed and BUA with apparent density. New correlations of inverse sound speed square and BUA with apparent density are suggested.

• Journal of Environmental Science International
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• v.28 no.5
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• pp.503-509
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• 2019

To prevent environmental pollution caused by leakage of leachate from waste landfill, vinyl acetate-ethylene (VAE) resin is applied to liner and cover materials to improve their performance. Styrene, styrene butadiene rubber, and VAE are widely used as polymer resins that have excellent water resistance and durability. Further, VAE resin is known to have additional advantages such as adhesion to nonpolar materials and resistance to saponification as a copolymer. In this study, the effect of VAE content on the properties of liner and cover materials was studied. The water and air content ratios, bending and compressive strengths, water absorption ratio, and coefficient of permeability of these materials were measured. The liner and cover materials with 4 wt% VAE showed good properties.

• Elastomers and Composites
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• v.57 no.2
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• pp.62-72
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• 2022

Passive daytime radiative cooling (PDRC) is attracting increasing attention as an eco-friendly technology that can save cooling energy by not requiring an external power supply. An ideal PDRC structure should improve solar reflectance and emissivity within the atmospheric spectral window. Early designs of photonic crystal materials demonstrated the benefits of PDRC. Since then, functional arrangements of polymer-based radiative cooling materials have played an important role and are rapidly expanding. This review summarizes the known inorganic, organic, and hybrid materials for PDRC. The review also provides a complete understanding of PDRC and highlights its practical applications.

• Elastomers and Composites
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• v.57 no.3
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• pp.81-91
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• 2022

Composites based on engineering thermoplastics exhibit excellent mechanical and thermal properties and simple processing and reprocessing attributes, and are widely used in the aerospace, three-dimensional (3D) printing, and automobile industries. Polyphenylene sulfide (PPS) is one of the most desirable engineering thermoplastics, owing to its superior thermal performance, inherent flame retardancy resulting from the presence of sulfur in its backbone structure, chemical resistance, and satisfactory electrical properties. However, pure PPS resin has limited applicability owing to its brittleness. To compensate for these shortcomings, various filler materials are frequently used in the manufacture of PPS composites. In this review, we would like to present the correlation between the structure and physical properties of PPS composite materials using various fillers.

• Elastomers and Composites
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• v.53 no.4
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• pp.220-225
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• 2018

Resilient pads play a major role in reducing the impact of loads on a rail in a rail-fastening system, which is essentially used for a concrete track. Although a compression set test is commonly used to measure the durability of a resilient pad, the static spring constant is often observed to be different from the fatigue test. In this study, a modified compression set test method was proposed to monitor the variations in the compression set and static spring constant of a resilient pad with respect to temperature and time. In addition, the life of the resilient pad was predicted by performing an acceleration test based on the Arrhenius equation.

• Science of Emotion and Sensibility
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• v.15 no.2
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• pp.177-182
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• 2012

Automotive sub-mat carpet for convenience and comfort of floor administration is additional supplemented floor mat. Sub Mat Backing of the current vehicle's materials reclaimed rubber, PVC, etc. are used, but secondary rubber and PVC Backing have bad sound absorption. Also rubber is heavy too. Contact surfaces between PET staple fiber, PET non-woven, PVC backing and car's floor carpet was measured the coefficient of friction for each sub-mat's non-slip evaluation. A surface of PET non-woven sub-mat has the highest coefficient of friction. Each of sample was observed by optical microscope the contact surfaces before and after. Contact surfaces of PET staple fiber sub-mat was changed increasingly to non-woven. This fact is shown that the sub-mat would be tangled between its contact surface and top of the floor carpet. It is expected to be highly non-slip. In case of PET non-woven sub-mat had not different for contact surfaces between before and after. And PVC backing was shown lower non-slip than other samples. The result of optical microscope and coefficient of friction is seems to be related.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.167-174
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• 2022

The objective of this study is to evaluate the dynamic properties of DUS (damping-up system) composed of the materials with excellent damping capacity, and to compare with those of the conventional hangar bolt. The main parameters are the type and hardness (𝜂_H), of rubber and the prestress force (value converted from the compression strain (𝜂_R) in the stress-strain relationship of rubber). The dynamic properties were examined from the natural frequency (𝜔_n), maximum response acceleration (A_m), amplification coefficient (𝛼_p), maximum relative displacement (𝚫_m), and damping ratio (𝜉_D). The test results showed that the A_m, 𝛼_p, and 𝚫_m values of DUS were 46.3%, 46.6% and 62.9% lower, respectively, and the 𝜉_D value was 3.89 times higher, when compared to those of the conventional hangar bolt. In particular, the 𝛼_p value was 1.3 for DUS, and 2.45 for the conventional hanger bolt, which were similar to those of rigid and flexible components specified in KDS 41 17 00, respectively. Consequently, in the optimal details of DUS, the 𝜂_H values of 50 and 45 were required for the NR (natural rubber) and EPDM (ethylene propylene diene monomer), and the 𝜂_R value of 5% was also recommended.

• Transactions on Electrical and Electronic Materials
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• v.4 no.3
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• pp.25-28
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• 2003

Radiation technology is an effective way for regulating polymeric materials to physicochemical and mechanical properties. New polymeric hydrogels based on vinyl ethers have been synthesized by the $\gamma$-initiated polymerization method. In this paper, we have studied the effect of radiation on mechanical and electrochemical properties of new rubber-like polymeric composite materials based on polyvinylether of ethyleneglycol (PVEEG).